Subsurface hydraulic pump assembly with reverse flow



June 13, 1961 c. 1 ENGLISH SUBSURFACE HYDRAULIC PUMP ASSEMBLY WITH REVERSE FLOW Filed Dec. 14, 1959 5 Sheets-Sheet 1 FIEL- l June 13, 1961 C. L. ENGLISH SUBSURFACE HYDRAULIC PUMP ASSEMBLY WITH REVERSE FLOW Filed Deo. 14, 1959 5 Sheets-Sheet 2 INVENTOR. CHA @Les o MqL/"s/-f www June 13, 1961 c. L. ENGLISH 2,988,005

suBsURFAcE HYDRAULIC PUMP ASSEMBLY WITH REVERSE FLow Filed Deo. 14, 1959 5 sheets-sheet s waff o W P/GT4 INVENTOR. F l' EL 5 CHA/2LH WGA/5H WMM@ Arrow/5r June 13, 1961 c. l.. ENGLISH 2,988,005

SUBSURFACE HYDRAULIC PUMP ASSEMBLY WITH REVERSE FLOW Filed Dec. 14, 1959 5 Sheets-Sheet 4 F j E 5 HVVENTUR. CHA/L55 L., CA/@MSH TTOPNFY `lune 13, 1961 c. ENGLISH 2,988,005

sUBsUREAcE HYDRAULIC PUMP ASSEMBLY WITH REVERSE FLOW l5 1 402 s 598 aaa 564 36o V lL/f 654 355 4562 55a J5 FIEE I4,

f-4/ IN V EN TOR.

CHAQLc-s L, lum/5H lay/@MMM A frog/Vey `nited States Filed Dec. 14, 1959, Ser. No. 859,218 20 Claims. (Cl. 10S-46) 'Ihis invention relates generally to improvements in the art of subsurface hydraulic pump assemblies, and more particularly, but not by way of limitation, to an improved tree pump type of subsurface pump installation wherein the ilow of fluid through the tubing strings is reversed with respect to the practice presently followed in the Related subject matter is disclosed and claimed in my U.S. Patent No. 2,917,000 entitled Subsurface Hydraulic Pump Assembly, issued December 15, 1959.

As it is well known in the oil producing industry, it is common practice to provide a well installation for subsurface hydraulic pumps utilizing parallel strings of tubing extending downwardly in the well and interconnected at their lower ends in such a manner that a hydraulic pump may be pumped downwardly through one of the tubings into a pumping position, and then, at a 'later time, the hydraulic pump may be pumped back upwardly to the surface through the same tubing. The most popular Well installation of this general type is illustrated in U.S. Patent 2,338,903 which discloses the use of a large and a small string of tubing extending downwardly in a well in side-by-side relation. A housing is secured on lthe lower end of the larger string of tubing and the smaller string of tubing is connected to the lower end portion of this housing. Such housing forms a hydraulic pump receiving cavity 'arranged in such a marmer that a pump seated therein may be operated by high pressure power fluid llowing downwardly through the larger string of tubing. In this 'type of installation, the hydraulic pump unit pumped downwardly through lthe larger tubing into the pump cavity, and is automatically placed in operation when seated in the pump cavity, to force well fluid and exhausting power lluid upwardly through the smaller string of tubing. When it is desired to remove the pump, the liow through the large and small strings of tubing is reversed, and the pump unit is forced upwardly through the larger string of tubing in the nature of a piston. Therefore, type of system is known in the art as a free pump system.

Free pump systems possess several substantial advantages over the more conventional type of installation wherein a hydraulic pump is suspended on the lower end of a string of power tubing, and free pump systems have been widely accepted i-n the industry. The most notable advantage of a free pump system over a suspension type system is in the time required for removing a subsurface hydraulic pump from the bottom of a well for repair or the like. As indicated above, in a tree pump system, the pump unit isy merely pumped to `the surface through the larger string of tubing; whereas in a suspension type of pump installation the power tubing must be removed from the well to raise the hydraulic pump-which is a time consuming and expensive opera-tion. However, a free pump system, as it is commonly used in the industry, possesses distinct disadvantages.

When using a subsurface hydraulic pump wherein the engine end and the pump end of the unit are of substantially ille same size, the volume of lluid forced to the surface of the well by the pump is substantially twice the amount of uid forced downwardly to operate the pump. The total volume of uid raised by the pumping unit comprises exhausted power flu-id which has been used to operate -the pump, and -well fluid drawn into the pump vfrom the Awell bore. Since the larger volume of uid atent is forced upwardly through the smaller string of tubing, substantial resistance to flo-w of this lluid is encountered and the efficiency of the pump unit cannot be obtained. Also, each time the ow in the strings is reversed, as when fa soluble plug is forced down the small tubing to remove parain therefrom, the pumping unit is removed from the pump cavity and must be reseated before production can be resumed. Furthermore, a portion of the dirty well lluid invariably enters the engine end of the pumping unit each time the ilow in the parallel tubing strings is reversed, to damage the intricate hydraulic valve mechanism therein.

Several different systems have .been devised to utilize a pair of parallel large and small tubing strings, wherein the high pressure power fluid can be fed down the smaller tubing and the larger: volume of lluid pumped upwardly through the larger string of tubing, and still have the pump freely removable through the larger string of tubing. However, in each of these previous systems,l

a more complex housing construction on the lower end of the larger string of tubing is required. Inother words,

these systems require a change in design of the pump cavity in which the pump unit is seated. As a result, these systems cannot be used in an existing free pump installation without removing both the larger and smaller strings of tubing and replacing the pump cavity housing; hence these reverse ilow type of systems have not replaced prior free pump systems to any materiall extent. Also, in these systems, as well as in a conventional free pump system, a substantially pressure must be created in vthe lower portion of the pump cavity to initially unseat the pumping unit.

In all installations of subsurface hydraulic pumps, the pumping unit is seated in a tubular seating shoe and is provided with a packer around the medial portion of the pumping unit in upwardly spaced relation from the seating shoe having a diameter larger than the inner diameter of the seating shoe. In all of the previous systems, the pumping unit is unseated by the imposition of high pressure fluid between the packer and the seating shoe which acts on the downwardly facing portion of the packer and pumping unit. However, the extreme lower end of the pumping unit which is disposed within the seating shoe is subjected to only well luid pressure. Therefore, a downwardly acting hydraulic bias is imposed on the lower end of the pumping unit which must be overcome by the high pressure uid acting on the downwardly facing area of the pumping unit between the packer and seating shoe. This downwardly acting hydraulic bias, in combination with friction provided by seating cups around the lower end of the pumping unit and by the packer (particularly when the pumping unit has been in the pumping cavity for an extended period of time) are di'icult to overcome and frequently require an excessive amount of pressure for unseating the pumping unit. Heretofore, the only answer to this problem has been a reduction in the size of the inner diameter of the seating shoe, which inherently restricts the size of the well fluid inlet of the pumping unit and obviously has practical limits.

The present invention provides what may be considered an improvement on a conventional free pump system and has been devised to utilize the existing parallel larger and smaller tubing strings and the pump cavity of a conventional free pump system. In accordance with the present invention, the pump assembly is pumped downwardly throughthe larger string of tubing and seated in the pump cavity; whereupon the pump unit is placed in operation by feeding high pressure power fluidH downwardly through the smaller string of tubing. uThe pump assembly includes means for directing uid having a pressure greater than well lluid pressure into the seating shoe above the usual tubing standing valve to overcome all downwardly acting hydraulic bias on the pump assembly, such that the pump assembly may be easily unseated from the -pump cavity and removed upwardly through the larger string of tubing. The present invention also'contemplates a pump assembly construction wherein the flow through the large and small strings of tubing may be reversed at will for such things as forcing soluble plugs down the larger string of tubing to remove parain and the Iike, without unseating the pump assembly. Furthermore, the present invention contemplates a novel bypass construction at the upper end of the pump assembly, whereby the pump assembly may be removed through the larger string of tubing by forcing high pressure fluid downwardly through the smaller string of tubing. Finally, the present invention contemplates a novel bypass construction at the upper end of the pump assembly which allows the pump assembly to be partially removed .from the well and then reseated without the necessity of completely removing the pump assembly, as in previous systems of this general tvpe- Broadly stated. the present invention may be defined as the combination of: a production tubing extending downwardly into a well, a power tubing extending downwardly into the well and connected at its lower end to the lower end portion of the production tubing, a supply of high pressure fluid connected to the production and power tubings for alternately subjecting7 said tubings to high pressure fluid. an annular seat in the lower end of the production tubing below the connection of the power tubing to the production tubing, a seating shoe engaging said annular seat. an upwardly opening standing valve assembly carried by the seating shoe for admitting well fluid into the seating shoe and restricting downward iiow of fluid through the seating shoe. an elongated pump assembly seated in said shoe and having a well liuid inlet vin its lower end communicating with said seating shoe for retaining well fluid pressure in said seating shoe during operation of the pump assembly and providing `a downwardly acting hydraulic bias on the pump assembly` said 'pump assembly having an exhaust port above said wel] fluid inlet, a packer carried by the pump Vassembly between said well fluid inlet and exhaust port to form an annular 'chamber between said packer and annular seat, said power tubing being in communication with said chamber, and means for directing fluid from said chamber into said seating shoe against the standing valve as* semblv and overcoming said downwardly acting hydraulic bias for unseating the pumn assembly.

An important object of this invention is to utilize an existing free pump tubing and pump cavity installation and yet provide a downward flow of high pressure power fluid through the smaller tubing and an upward flow of production fluid through the larger tubing.

Another object of this invention is to provide a subsurface hydraulic pump assembly and installation wherein the 'subsurface pump may be partially removed from the well and then reseated in a pump cavity at the lower end of the well.

A further object of this invention is to provide a subsurface hydraulic pump installation utilizing a pair of parallel tubing strings wherein the fluid flow may be reversed in the tubing strings without aiecting the seating position of the pump and without passing dirty well fluid through any portion of the intricate pump mechanism.

Another object of this invention is to provide a subsurface hydraulic pump installation utilizing large and smallv tubing strings extending downwardly in a well, wherein the tubing strings provide a minimum resistance to the flow off fluid therethrough during a normalipumping operation. Y p

A stillv further object of this invention is to provide a subsurface hydraulic pump installation wherein all of the downwardly acting hydraulic bias .on the pump assembly is removed when the pump assembly is being unseated.

Another object of this invention is to provide a subsurface hydraulic pump installation wherein the pump assembly may be pumped out of a well withV a minimum hydraulic pressure, yet the pump assembly will be stable during a normal pumping operation.

A further object of this invention is to provide a subsurface hydraulic pump installation which is simple in construction, may be economically manufactured and which will have a long and trouble free service life.

Other objects and advantages of the invention will be evident from the following detailed description, when read in conjunction with the accompanying drawings which illustrate my invention.

In the drawings:

FIGURE 1 is a vertical sectional View through a poi'- V tion of a well bore schematically illustrating a well installation constructed in'accordance with this invention.

FIGURE 2 is a vertical sectional view through the upper portion of a pump assembly and pump cavity constructed in accordance with this invention. p

FIGURE 3 is a continuation from the lower end of FIG. 2 and illustrates the construction of the lower portion of a pump assembly andpump cavity.

FIGURE 4 is an elevational view of a retriever for the pump assembly illustrated in FIGS. `2 and 3, with the lower portion of the retriever being shown in section to illustrate details of construction.

FIGURE 5 is a schematic vertical sectional view through a pump assembly and pump cavity of the type shown in FIGS. 2 and 3, illustrating a seating or removing operation of the pumpassembly.

FIGURE 6 isa schematic sectional view through a portion of the pump assembly and pump cavity .illustrated in FIG. 2, showing operation of the pump assembly when flow through the parallel tubings is reversed.

FIGURE 7 is a vertical sectional view through the upper portion of a modiiied pump assembly which may be utilized with a pump assembly lower portion of the type illustrated in Fig. 3.

FIGURE 8 is a schematic sectional view through a pump assembly and pump cavity of the type illustrated in FIGS. 7 and 3, illustrating a seating yor removing operation of the pump assembly.

FIGURE 9 is a view similar to FIG. 8, illustrating the normal pumping position of the pump assembly.

FIGURE 10 is a vertical sectional view through a modified bypass assembly which may be utilized on the pump assembly illustrated in FIG 7.

FIGURE 11 is a view similar to FIG. l0 illustrating a second and closed position of the valve assembly in thc bypass.

FIGURE 12 is a vertical sectional view through another modilied bypass assembly., illustrating the position of the bypass valve means when the pump assembly to which the bypass assembly is connected is in a pumping position.

p YFIGURE 13 is a view similar to FIG. 12, schematically illustrating the position of the bypass valve means when Y the pump assembly is being forced downwardly into pumping position.

FIGURE 14 is another view similar to FIG. 12, schematically Villustrating the position of the bypass valve means when the pump assembly is being pumped out Vof a well.

FIGURE l5 is an elevational View of the ratchet member utilized in the'valve means illustrated in FIGS.

l2, 13 and 14, with, the ratchet member'being laid out llat to illustrate; details of construction.

Before proceedingwith ra detailedLdescription of .my

Y invention, it would be welll to; note, the; various pressures of the uidsrrused and, encounteredin. the operationof subsurface hydraulic pumps in Yoil wells. In most oil mme wells the pressure of the iluid standing in the well bore is at a relatively low pressure, at least at the normal level of installation of a subsurface pump, and the well fluid is normally considered to be at zero presure. However, since a subsurface hydraulic pump is normally positioned several thousand feet deep, oil standing in tubing extending from the top of the well down to the level of the pump will have a relatively high static pressure, such as one to two thousand pounds, at the depth of the pump. It therefore follows that the power iiuid (usually oil) forced downwardly through a string of tubing t the pump will have a pressure at the depth of the pump equal to the static pressure, plus the pressure produced by the surface pumping equipment (disregarding friction). In the present specification and claims, this pressure of the power uid used to operate the pump will be considered as pump operating pressure. It will be apparent that these various presures will not only alect the operation of the pump, but also the forces required to be overcome in uuseating the pump. In addition to these usual pressures in and adjacent the pump, the present invention contemplates the use of pressures between the static and pump operating pressures which are obtained from the power uid in any desired manner, such as managing the amount of uid llowing from the surface pumping equipment into the well tubing being utilized.

Referring to the drawings in detail, and particularly FIG. l, reference character 20 designates a well bore containing the usual casing 22 having a well head assembly 24 on the upper end thereof. A large string of tubing 26 and a smaller string of tubing 28 are suitably secured to the well head assembly 24 and extend downwardly through the casing 22 in parallel relation. In this specication and claims, the larger tubing 26 shall be referred to as the production tubing and the smaller tubing 28 shall be referred to as the power tubing. The lower end 30 of the production tubing 26 is suitably connected to a housing 32 forming a pump cavity which receives a hydraulic pump assembly 34, as will be described in detail below. The power tubing 28 is connected to a medial portion of the pump cavity housing 32 for supplying high pressure power uid to the pump 34, as will also be described in detail below. A gas anchor 36 is normally secured on the lower end of the pump cavity housing 32, as is conventional in the art.

The upper end of the production tubing 26 is closed by a suitable cap 38 above the well head 24, and the upper end of the power tubing 28 is connected directly to one side of a control valve 40, such as a four-way valve having a suitable operating handle 42. The opposite side of the valve 40 is connected to an intermediate portion of the production tubing 26. The valve 40 is utilized to direct power uid at various pressures from a supply conduit 44 into either the power tubing 28 or the production tubing 26. An exhaust conduit 46 is connected to the valve 40 opposite the supply conduit 44 and communicates with a suitable storage tank (not shown) for receiving fluid flowing from either the power tubing 28 or the production tubing 26. lt will be understood that the supply conduit 44 is connected to a suitable pump and power fluid supply.

In one embodiment of this invention (FIGS. 2 and 3) the pump assembly 34 comprises an elongated pump unit 48 having a seating member 50 secured on the lower end thereof as illustrated in FIG. 3. The seating member is adapted to seat in a tubular seating shoe 52 when the pump assembly is in pumping position. The seating shoe 52 is in the form of a tubular body 54 having a downwardly and inwardly tapered surface 56 on the outer periphery thereof arranged to mate with an upwardly facing annular seat 58 suitably secured in the pump cavity housing 32. An upwardly opening standing valve assembly l60 is provided in thev lower end portion of the seating shoe 52 and comprises a valve seat member 62 threaded into the lower end of the seating shoe body 54 to receive a valve' head 64. The valve head 64 has guide rods 66 extending upwardly and downwardly from the central portion thereof. The lower valve guide rod 66 is extended through a suitable guide member 68 formed in the seating member 62, and the upper guide rod 66 extends through a tubular insert 70 suitably held in the lower portion of the body 54 by the seating member 62. 'It will also be noted that a spring 72 extends around the upper valve guide rod 66 and is positioned between the guide member 70 and a head 74 suitably formed on the upper end of the upper valve guide rod. The spring 72 functions to bias the valve head 64 upwardly to an open position with a relatively slight force, as will be more fully hereinafter set forth. It may also be observed that a hollow plug 76 is secured in one side of the seating shoe body 54 to facilitate the draining of fluid through the seating shoe 52 in a manner common to the art. The upper end 78 of the seating shoe 52 is provided with a counter bore 80 to receive the lower end portion of the seating member 50 of the pump assembly 34.

- The seating member 50 comprises a main body portion 82 having a vertically extending passageway 84 therethrough and being internally threaded at its lower end to receive the upper threaded end of a tubular mandrel 86. The mandrel 86 is provided -with suitable packing 88 around the outer periphery thereof held between a shoulder 90 formed around the mandrel 86 and the lower end of the main body portion 82 of the seating member. The packing 88 is of a size to sealingly engage the walls of the counter bore 80 of the seating shoe 52 when the pump assembly 34 is seated in pumping position as illustrated in FIG. 3. It will also be observed in FIG. 3 that the bore extending through the mandrel 86 communicates with the passageway 84 extending vertically through the main body portion 82 of the seating member 50.

A passage 92 extends transversely through a portion of the body 82 and then vertically to the upper end of the body 82. A combination valve guide and seating member 94 is threadedly secured in the upper end of the passage 92 to receive a downwardly opening ball type valve member 96, hereafter referred to as the recovery valve. A trip rod 98 is slidingly secured in the combination guide and seat member 94 and is provided to unseat the recovery valve 96 when moved downwardly, as will be hereinafter set forth. Also, a spring 100 is positioned in the member 94 between a shoulder 102 formed on the trip rod 98 and a locking ring 104 suitably secured in the upper end of the member 94. The spring 100 functions to provide a ,relatively weak downwardly acting bias on the trip rod 9S and recovery valve 96, tending to open the recovery valve, as will be described in more detail below.

A ytubular extension 106 is threadedly secured around the upper end of the main body member 82 of the seating member 50 and is provided with an inwardly extending circumferential flange 108 on the upper end thereof to cioe operate with a tubular extension 110 on the lower end of the pump unit 48, as will be described. The extension 1110 is provided with suitable packing 112 around the outer periphery thereof which is held in the desired position in a suitable groove of a flange 114. Ihe packing 112 is of a size toprovide a sliding, sealing engagement thereof with the inner periphery of the seating member extension 106 and prevent leakage around the extension 110 during operation of the pump assembly. A valve actuating member 116 is suitably secured in the extension 110 and may take any desired form which will not materially restrict the flow of fluid through the extension 110, but yet is arranged to contact the upper end of the trip rod 98 upon downward movement of the extension 110 during uuseating and seating of the pump assembly- 34, as will be described. It should also be noted in FIG.` 3 that the outer diameter of the seating member 50r is substantially less than the inner diameter of the ad- 7 jacent portion of the pump cavity housing 32 to provide an annular space 118 between the seating member and pump cavity housing which communicates with the ,lower end of the power tubing 28.

The pump unit 48 comprises, generally speaking, a pump cylinder connected to a motor cylinder 122 (see FIG. 2) by means of what is commonly known as a middle plug 124. Referring back to FIG. 3, it will be observed that the pump cylinder 120 has an outer diameter substantially less than the inner diameter ofthe adjacent portion of the pump cavity housing 32 to provide a continuation of the annular chamber 118 around the seating member 50. A tubular head 126 is secured in the lower end of the pump cylinder 120 and forms a connection for the upper end of the extension 110 previously described. Also, the head 126 forms a well fluid inlet 128 for the pump unit 48, and is provided with an upwardly facing-valve seat 130 therein to receive a standing valve 132. The rod 134 of the standing valve 132 is guided by a suitable spider type of mechanism 136 which may be easily formed as a portion of the head member 126. It will be apparent thatl when the standingl valve 132 is closed, no fluid can flow downwardly through the well fluid inlet 128 into `the extension 110. However, the standing valve 132 is responsive to'an upwardly acting pressureV force to open the well iiuid inlet 128 during operation of the pumping unit 48, as will be described in detail below.

The pump piston 138 of the pump unit 48 is provided with suitable piston rings 140 to provide a sliding lit thereof in the pump cylinder 120, and is provided with a vertical passageway 142 therethrough. The lower end of the passageway 142 is alternately closed and opened by a suitable traveling Valve 144 cooperating with an upwardly facingvalve seat 146, such that the pump piston 138 will provide a sucking action in the lower portion of the pump cylinder 120during the upstroke of the pumping unit, as will be described. A tubular connecting or middle rod 148 is secured to the upper end of the pump piston 138 and extends vertically upward through the *f middle plug 124 into `connection with an engine piston assembly 150 mounted in the engine cylinder 122.

The engine piston assembly 150 may be of any desired construction which will provide a reciprocation of the engine piston assembly `150 and the pump piston 138 when high pressure power fluid is introduced into the lower end of the engine cylinder 122. The engine piston assembly directs the high pressure power fluid into the upper end portion of the engine cylinder 122, and, alternately, exhausts this power fluid downwardly through the hollow connecting rod 148 to provide a reciprocation of the engine piston assembly. The detailsA of const-ructionrofY the enginepistonassembly 150 formno part of the present inventionand are therefore not described in detail herein.

The'middle plug 124 comprises an elongated body portion V152 havingV a bore 154y extending longitudinally there-V throughof a sizerto loosely receive the hollow connecting rod 148 and-provideV an annular passageway 156 between the wallsof the bore 154 andthe outer periphery of the rod 148. The annular passageway 1756 communicates with'anupwardly and outwardly extending exhaust port 158-and1provides-communication between the pump cylinder'120 and Vthe interiorrof the pump cavity housing 32 around the engine end portion of the pump unit 48.

A packerlllis secured around the outer periphery of the middle plug 124 below the port 158 by suitable spacer rings.162 andi164, With-the ring 164 being threadedly secured to the lower end portionof. thebody 152 and Vurgingthe. upper ring 162-against a shoulder 166 on the body:,152. Theipackery 160;is of a size tosealin'gly enmunicates with ports formed through the lower ring 164, which in turn communicate with the annular chamber 1,18 surrounding the pump unitV 48 between the packer 160 and the annular seat 58 (see FIG. 3). As previously indicated,` the annular chamber 118 is in constant communication with the lower end of the power tubing 28. The upper end of the annular chamber 168 (FIG. 2) communicates with one or more vertically extending passageways 172 extending on upwardly `to the upper end of the middle plug body 152. The upper end of the passageway 172 communicates with an annulla-r chamber 174 formed around the engine cylinder 122 by a jacket 175 threadedly secured at its lower end to the upper end portion of the middle plug 124.V The annular chamber 174 in turn communicates with ports 176 formed in the lower end portion of the engine cylinder 122. Therefore, constant fluid communication is provided between the lower end portion of the engine cylinder 122 and the annular chamber 118 for supplying high pressure power iluid from the power tubing 28 to the engine end of the pump unit 48, as will be described in more detail below. In this connection, it may be noted that the passageway 172, chamber 168 and ports 170 may be considered as a single continuous passageway 172 through the middle plug 124-providing constant communication between the annular chambers 118 and 174.

The jacket 175 which forms the annular chamber 174 around the engine cylinder 122 is provided with a suitable head portion 178 held in sealing engagement with the upper end 180 of the engine cylinder 122 to close off the engine cylinder 122 and prevent the escape of uid from the upper end 180 of the engine cylinder. It will lalso be noted in FIG. 2 that a wire line puller or iishing neck182 is formed on the upper end of the head 178 to facilitate removal of the pump assembly 34 from the well installation, as will be described.

Referring again to the middle plug 124it will be observed` that counter bores 184 and 185 are formed at'the upper end of the bore 154 extending longitudinally through the middle plug body 152 to receive a novel packing device 186. The packing device 186 comprises a tubular mandrel 188 of a size to slidingly lit in the counter bore 184'and having a reduced diameter portion 189 on the lower end thereof slidingly fitting in the counter bore 185.V Suitable packing 190 is secured in the mandrel 188 against an upwardly facing shoulder 191 by a follower 192 threadedly secured in the upper end of the mandrel.

Also, an O-ring 193 is secured in a mating groove around the lower end portion 189 of the mandrel to engage the walls of the counterbore 185. Thus, the packing device 186 provides a seal around the middle rod 148 to prevent leakage of 'fluid through the middle plug 124 when the packing device is in the position shown in FIG, 2. However, the packing device 186 may be moved upwardly by pressure dilferentialsf against a stop 194 threadedly secured in the upper end of the counterbore 184 to provide communication between bypass ports 195 in the lower end portion 189 of the mandrel anda restricted port 196 in the side of the middle plug body 152 communicating with the vertical passageway 172.' It should also be pointed out that the stop 194 is so located that the extreme lower end of the mandrel 188 will not be removed from the smaller counterbore when the aaselhejinnenperiphery ofthe.. pump4 cavity v.housing 32 animando-a s ealloftha .pump 11nit48sin-thehousinan arpunduthemiddleplug,*124. It willalso benoted; that;`

the Vrings 162 and 164'a`re of a size to provide an annular Operation of `embodiments Shown in FIGS. 1-6

As will be readily understoodby'those skilled in the art, theV production tubing 26 and power tubing 28 remain Y `in'the, well bore-20 at-all times, withY the pumpwcavity housing 32 connected to the lower ends ofthe productionV and power tubings as is conventional in a free pump system. Also, the seating shoe 52 and tubing standing valve 60 (shown in FIGS. 3 and 5) remain in the lower end of the pump cavity housing 32 until a malfunction of the tubing standing valve 60, or until it is desired to remove the tubings 26 and 28. It may be noted here that if it is desired to remove the tubings 26 and 28, a suitable tool may be lowered through the production tubing 26 and utilized to fracture the hollow plug 76 shown in the seating shoe S2 in FIG. 3; whereupon any fluid standing in the production and power tubings will be drained through the seating shoe 52 to facilitate the removal of the tubing strings. However, insofar `as the present invention is concerned, it will be assumed that the tubing standing valve 60 is in working order, the seating shoe 52 is installed in the lower end of the pump cavity housing 32, and the tubings 26 and 28 are full of oil.

When installing the pump assembly 34, the cap 38 (FIG. 1) is removed, then the pump assembly 34 is inserted in the upper end of the production tubing 26 and manually forced below the connection of the control valve 40 to the production tubing. The cap 38 is then replaced and the control valve 40 is turned to such a position that power iluid in the supply conduit 44 is directed into the upper end of the production tubing 26 above the pump assembly 34 at a slight pressure. In this embodiment of the invention, the inner diameter of the production tubing 26 is substantially equal to the inner diameter of the pump cavity housing 32, `such that the packer 160 (FIG. 2) around the middle plug 124 provides a sliding seal of the pump assembly 34 in the production tubing 26. However, the packer 160 does not need to provide a fluid tight seal with the inner periphery of the production tubing 26, since only a minor force is required to urge the pump assembly 34 downwardly through the production tubing 26. When power fluid is directed into the upper end of the production tubing 26, this fluid reacts on the packer 160 to force the pump assembly 34 downwardly into the pump cavity housing 32. It will be understand that fluid standing in the production tubing below the downwardly moving pump assembly 34 is forced up the power tubing 28 and into the exhaust conduit 46.

During the imposition of a higher pressure above the pump assembly 34 than below the pump assembly 34 to force the pump assembly downwardly in the production tubing, the higher pressure liuid will gain access to the pump cylinder 120 (FIG. 2) through the passageway 158 and annular passageway 156. However, this uid will be prevented from flowing on downwardly through the pump cylinder 120 by the traveling valve 144 (FIG. 3) in the pump piston 1318. This relatively high pressure fluid in the upper end portion of the pump cylinder 120 will act upwardly on the lower end of the packing device 186 positioned around the middle rod 148 and force the packing device upwardly against the stop 194 as shown in FIG. 6. In this latter position of the packing device 186, uid from the pump cylinder 120 will leak out through the ports 195 and 196 into the pasasgeway 172, and thence downwardly into the annular chamber 118. However, since the port 196 is restricted, a very minor leakage of fluid will occur. A leakage of a small portion of iluid through the upper end of the annular passageway 156 will not alfect the downward movement of the pump assembly, and the tiuid which does leak through the pump assembly will merely be directed back upwardly through the power tubing 28. The only requirement for a downward movement of the pump assembly 34 is that the pressure above the pump assembly be slightly greater than the pressure below the pump assembly.

As the pump assembly 34 becomes seated in the pump cavity housing 32 with the packing 88 on the seating member 50 in the upper end of the seating shoe 52, the extension 110 on the lower end of the pump unit 48 will be telescoped into the seating member 50, as illustrated 1G in FIG. 5. the extension holds the trip rod 98 downwardly and holds the recovery valve 96 in an open position. When the packing 88 is completely seated in the seating shoe 52, with the lower end "86a of the seating member 50 in contact with a tapered surface 54a in the seating shoe 52',

which may be indicated by an increase in pressure at the" top of the production tubing 26, the control valve 40 is shifted to provide communication between the power fluid supply conduit 44 and the upper end of the power tubing 28. Thus, the power tubing 28 will be subjected to high pressure power fluid, preferably at pump operating pressure, and the production tubing 26 will be connected with a lower pressure through the exhaust conduit 46, such that the pressure in the production tubing 26 directly above the pump assembly 34 will be equal to the static head of the fluid standing in the production tubing.

As illusrated in FIG. 5, a portion of the high pressure fluid fed through the power tubing 28 into the annular chamber 118 around the lower end portion of the pump assembly 34 will flow through the passage 92 around the recovery valve 96 into the seating member 50 and hold the tubing standing valve assembly 60 closed. Simultaneously, the high pressure Huid in the annular chamber 118 will react in a downward direction on the seating member 5() across an area equal to the difference in cross sectional areas of the packing 88 and the packing 112, while reacting in an upward direction on the downwardly facing portion of the pump unit 48 between the packer 16) and the packing 112 to simultaneously hold the seating member 50 down and urge the pump unit 48 upwardly in the pump cavity housing 32. This upward movement of the pump unit 48 raises the extension 11d in the upper end of the seating member 50 and releases the trip rod 98 from contact with the extension 110. As soon as the trip rod 98 is released by the pump unit extension 110, the hydraulic force imposed on the recovery valve 96 by virtue of the iluid flowing through the passage 92 around the valve 96 will overcome the force of the spring 100 and close the valve 96. However, the pump unit 48 is moved on upwardly after closing of the valve 96, such that the extension 110 provides a pumping action in the seating member 50 and seating shoe 52 to reduce the pressure therein to a pressure equal to the pressure of uid standing in the well bore 20. This pumping action is accomplished since the pump standing valve 132 will remain closed during upward movement of the pump unit 48, and the tubing standing valve 64 will open as flow through the passage 92 is stopped. Therefore, when the pump unit 48 is moved upwardly to such an extent that the flange 114 on the lower end of the pump unit extension 110 contacts the inwardly extending flange 108 in the upper end of the seating member 50, well uid pressure is present in the seating member 50 and seating shoe 52, and high pressure fluid is present in the chamber 118 around the lower end portion of the pump assembly 34,

With the pump assembly 34 in pumping position as illustrated in FIG. 3, the high pressure fluid present in the power tubing 28 iows upwardly through the annular chamber 11'8, passageway 172 in the middle plug 124 (see FIG. 2) into the lower end of the annular chamber 174 surrounding the engine cylinder 122, and then through the ports 176 into the lower end of the engine cylinder 122 to operate the engine piston assembly in the manner previously described. It may also be noted that this high pressure fluid acts downwardly on the upper end of the packing device 186 to move the packing device 186 down to the position shown in FIGS. 2 and 5 in sealing relation around the middle rod 148. It may also be noted that the minor flow of high pressure uid through the ports 196 and 195 from the passageway 172 will provide no appreciable upward force on the lower end of the packing device. Also, in the position of the packing In this position of the pump assembly 34,V

1 l device 186 shown in FlGS. 2 and 5, the ports 196 and 195 are closed.

During the upstroke of the engine piston assembly 150, movement is translated through the middle rod 148 to raise the pump piston 138 and draw well uid upwardly through the tubing standing valve assembly 60, seating shoe 52, passageway 84 of the seating member 50 and through the pump standing valve 132 into the lower end portion of the pump cylinder 120. Also, the engine piston assembly 150 operates to exhaust used power lluid downwardly through the hollow middle rod 1418 and the upper end portion of the pump piston 138 into the upper end portion of the pump cylinder 120 during this stroke of the pump. Upon a downward movement of the pump piston 138, the fluid in the lower portion of the pump cylinder 120 is forced upwardly through the traveling valve seat 146 and the passageway 142 into the upper end of the pump cylinder 120.

rl`he pump piston 138 forces iluid upwardly through the passageways 156 and 158 into the annular chamber formed between the production tubing 26 and the upper end portion of the pump assembly 34 during each stroke of the pump unit. However, the major portion of the ow of fluid from the pump cylinder 120` upwardly into the production tubing 26 will be on the upstroke of the pump piston 138, such that the pump is basically a single acting pump. In any event, the fluid pumped by the pump piston 138 ilows upwardly through the production tubing 26 to the surface of the well for discharge through the exhaust conduit 46 to suitable storage facilities. It may also be noted here that Since the uid owing upwardly through the production tubing 26 is a combination of exhausted power fluid and well uid drawn upwardly into the pump cylinder, the volume of fluid flowing upwardly through the larger production tubing 26 will be substantially more than the volume of fluid `flowing downwardly through the smaller power tubing 28, such that the minimum resistance to the flow of uid to and from the pump assembly 34 will be encountered. Furthermore, the action of the pump piston 138 andthe pump standing valve 132 provides well fluid pressure in the seating member 5t) and seating shoe 52 during operation of the pump unit. It should also be noted here that the spring 72 holds the tubing standing valve 64 open during pumping action of the pump unit 48 to assure that well fluid pressure remains in the seating shoe 52 and seating member 58.

As will be readily understood by those skilled in the art, the hydraulic .forces affecting the position of the pump assembly 34 during a pumping operation comprise an upwardly acting force resulting from the imposition of high pressure fluid on the downwardly facing area of the pump assembly between the packer 160` and the .lower packing 8S; and the downwardly acting forces on the pump assembly comprise static uid pressure acting downwardly across the entire cross sectional area of the pump assembly, plus the downwardly acting hydraulic bias provided by the substantially lower well lluid pressure acting across the cross sectional area of the packing 88. In a commercial application of this invention, the difference in cross sectional area between the packer 1160 and the lower packing 88 will be retained as small as maybe practical to assure that the hydraulic forces imposed on the pump assembly 34 will provide a net downwardly acting force to maintain the pump assembly stable in the pump cavity housing 32. For example, this dilerence in when high pressure power fluid is present in the annular chamber 118 Aand acting in a downward direction o'n this packing material. Finally, it will be apparent that since the annular seat 58 and the seating portion 56 of the seating shoe 52 are tapered downwardly and'inwardly, the net hydraulic force on the seating shoe 52 will always be in a downward direction to hold this member in operating position in the pump cavity housing 32.

In order to remove the pump assembly 34, the control valve 40 is shifted to direct high pressure iluid into the upper end of the production tubing 26 and connnect the upper end of the power tubing 28 Vto the exhaust conduit 46. This reversal of ow through the tubings 26 and 28 provides an imposition of high pressure fluid across the upper end of the pump assembly 34 and the imposition of static fluid pressure in the chamber 118 against the downvvardlyV facing areas of the pump unit between the packer 160 and thepacking 112. As a result, the pump unit 48 is forced downwardly to telescope the pump unit extension 110 in the upper end of the seating member 50 into the position shown in FIG. 5 to contact the trip rod 98 and open the recovery valve 96. The passage 92 therefore again provides communication between the chamber 118 and the interior of the seating member 50 and seating shoe 52 to increase the pressure in the seating member and seating shoe to the static pressure of uid standing in the power tubing 28. `This increase of pressure in the seating member 50 overcomes the downwardly acting hydraulic bias across the packing 112. lt may also be noted that a portion of the higher pressure fluid imposed above the pump assembly 34 will ilow downwardly through the passageway 158 into the upper end of the pump cylinder 120. This fluid will be prevented from llowing on downwardly (by the traveling Valve 144 in the pump piston 138), but a small portion thereof may flow into the chamber 118, since the packing device 186 will be moved upwardly against the stop |194 to open the ports 19S and 196. The pump assembly 34 may then be removed from the pump cavity housing 32 and the production tubing 26 in either of two ways.

In one method of removing the pump assembly 34, the control valve 4t) is placed in a neutral position to equalize the pressure of lluid in the power and production tubings. lt will then be noted that the hydraulic pressure forces across the pump assembly 34 will be neutralized and the pump assembly will remain in the position shown in FIG. 5, with the passage 92 being open to remove the downwardly acting hydraulic bias in the seating member Si). A suitable wireline retrieving device (not shown) is then lowered through the production tubing 7:26 and engaged with the fishing neck 182 on the upper end of the pump assembly.

As the wire line is pulled upwardly, the pressure of the uid in the power tubing 28 and annular chamber cross sectional areak may be designed to require Va` pressure in the chamber 118 twice as high as the'norrnal pump operating pressure to unseat the pump assembly 34. Also, the friction provided by the packer and the lower packing 88 will resistany upward movement of the pump assembly 34. In this connection it may be noted that the packing88` may be easily formed of Aa pressure type,gsuch as a Chevrontype ofvpacking,whicrh will be diticulttoremove'frorn the seatingmember' 50' 118 is gradually increasedV to provide an upwardly acting force on the downwardly facing portions of thepump assemblybetween the packer 160 and lower packing 83, such that a minimum pull is required on the wire line. it should be noted, however, that the` spring 168 should be of a strength to hold the recovery valve 96 open against the pressure of the lluid in the chamber 118; otherwise the recovery valve would close and a pumping action would be created in the seating shoe 52 during upward movement of the packing 88 and 112. It is believed apparent that the strength of thespring lill? may be selected to hold the valve 96 open `against a pressure somewhere between static and pump operating pressure and yet be overcome when pump operating pressure is provided in the chamber 118, asV when'moving the pump unit i8 upwardly into pumping position as previously described. The pump assembly 34 will then be free to moverupwardly through the production tubing yand the only re-Y sistance to this upwardV movenientg'will bebyY friction createdby Vthe packer" 160 against the wallsV of the pump'Vv cavity housing 32 and the production tubing 26, plus the weight of the pump assembly.

As an alternate method of removing the pump assembly 34, a retrieving device 200 of the type shown in FIG. 4 may be used. The retrieving device 200 comprises an elongated cylindrical mandrel 202 having three conventional swab cups 204, 206 and 208 suitably mounted thereon. The upper two swab cups 204 and 206 are turned downwardly and the lower swab cup 208 is turned upwardly, for purposes which will be described. Also, a iishing neck 210 may be formed on the upper end of the mandrel 202, if desired. The lower end of the mandrel 202 is provided with a threaded end 212 adapted to receive a housing 214 having a slip assembly 216 on the lower end thereof. The slip assembly 216 comprises a plurality of slip members 218 pivotally secured on the lower end of a rod 220, with the rod 220 extending upwardly into a bore 222 in the lower end of the housing 214. A spring 224 continually urges the slip assembly 216 downwardly to force the slip members 218 against the tapered face 226 of a slip housing 228 threadedly secured on the lower end of the housing 214. It will thus be apparent that the spring 224 continually urges the slips 218 downwardly and the tapered surface 226 of the housing 228 urges the slips toward one another in a contracting relation.

In use of the retriever 200, the cap 38 at the upper end of the production tubing 26 is removed and the retriever 200 is inserted in the upper end of the production tubing to a point below the connection of the production tubing with the valve 40. The cap 38 is then replaced and the valve 40 shifted to such a position that high pressure yfluid ows from the supply conduit 44 into the production tubing. This high pressure uid reacts on the upwardly facing swab cup 208 of the retriever 200 and forces the retriever downwardly through'the production tubing 26. During this downward movement of the retriever 200, sufcient pressure is applied on the uid in the production tubing 26 to telescope the pump assembly 34 into the position shown in FIG. 5 and to react on the lower end of the packing device 186 for forcing or holding the packing device 186 upwardly to the position shown in FIG. 6. It will then be apparent that uid iiowing downwardly through the production tubing ahead of the retriever 200 is by-passed through the passageway 156 and ports 195 and 196. This by-passing uid then flows downwardly through the passageway 172 in the middle plug 124 into the annular chamber 118 where it may be discharged upwardly through the power tubing 28. It may also be noted here that this by-passing of fluid through the pump assembly 34 upon the imposition of high pressure fluid in the production tubing 26 is very useful when it is desired to force soluble plugs (not shown) or the like downwardly through the production tubing for removing paraflin therefrom. These soluble plugs are frequently used in the art and it is believed sufficient to merely point out that the packing device 186 may be moved upwardly for a by-passing of fluid through the pump assembly when it is desired to use a soluble plug for paraffin removal.

As the retriever 200 reaches the upper end of they pump assembly 34, the lower end of the retriever housing 228 is moved downwardly over the fishing neck 182 of the pump assembly. The slips 218 will be moved upwardly in the housing 228 against the action of the spring 224 to open the slips and move the fishing neck 182 into the slips 218. When the retriever 200 is seated on the pump assembly 34, as will be indicated by an increase in pressure in the upper end of the production tubing 2,6, the valve 40 is again shifted to direct high pressure fluid into the power tubing 28 and connect the production tubing with lower pressure fluid. It should again be noted here that when the retriever 200 is seated on the pump as- 14 sembly 34, the pump assembly 34 will be telescoped into the position shown in FIG. 5.

Upon the imposition of high pressure Huid in the power tubing 28 and in the annular chamber 118 around the pump assembly 34 between the packer 160 and the lower packing 88, the packing device 186 will be moved down to the position shown in FIGS. 2 and 5, and a portion of the high pressure uid will tiow through the passage 92 around the recovery valve 96 into the seating member 50. The high pressure iiuid in the seating member 50 will be prevented from owing downwardly by the tubing standing valve assembly 60, and will be prevented from owing upwardly through the pump assembly by the downwardly facing swab cups 204 and 206 on the retriever 200. As a result, high pressure uid is present in the seating shoe 52 and in the chamber 118, and a net hydraulic force will be imposed on the pump assembly 34 and the retriever 200 in an upward direction. This force moves the pump assembly 34 upwardly through the production tubing 26 to the top of the well. It may also be noted that when an upward force is imposed on the downwardly facing swab cups 204 and 286 of the retriever 200, the slips l218 will be held against the fishing neck 182 by the tapered surfaces 226 of the retriever housing 228 to provide a positive connection of the retriever 200 to the pump assembly 34.

In briey reviewing the operation of the embodiment of this invention illustrated in FIGS. l through 6, it will be noted that the pump assembly 34 may be easily pumped downwardly through the production tubing 26 into a seating position in the pump cavity 32, with the pump unit extension telescoped into the seating member 50 in the position shown in FIG. 5. Upon a reversal in the flow of uid through the tubings 26 and 28, the pump unit is moved upwardly to provide a pumping action in the seating member 50 and seating shoe 52 to position the pump unit in a pumping position and provide well fluid pressure across the packing 88. The net hydraulic forces across the pump assembly 34 will then be in a downward direction to hold the pump assembly in pumping position and the pump unit may be operated in a normal fashion to pump well iiuids and exhausted power iiuid upwardly through the larger production tubing 26. When it is desired to unseat the pump assembly 34, the flow of fluid through the tubings 26 and 28 is again reversed to force the pump unit downwardly and telescope the pump unit extension 110 into the seating member 50; whereupon the downwardly acting hydraulic bias across the packing 88 is removed by an opening of the recovery valve I96. The pump assembly 34 may then be easily removed by use of a wire line or by use of the retriever 200. When the retriever 200 is utilized, the pump assembly 34 is pumped upwardly through the production tubing 26 in the nature of a free pump system. It may also be noted that uid may be forced downwardly through the production tubing 26, when the pump assembly 34 is seated in the pump cavity housing 32 for removing parafn Vfrom the production tubing, and then a normal pumping operation of the pump assembly may be resumed without a loss of time in removing the pump assembly 34 and in reseating the pump assembly.

Embodment shown in FIGS. 7-9

As previously indicated, this invention also contemplates a pump assembly construction which may be pumped upwardly and downwardly through the production tubing and operated by the imposition of high pressure power uid through the power tubing, without the necessity of using retrieving devices. This embodiment of the invention is illustrated in FIG. 7 and the pump assembly is generally designated by reference character 258. The pump assembly 250 is constructed'much in the same manner as the pump assembly 34 previously described, by utilizing the same construction from the middle plug 124 on downwardly to the lower end of the asados assembly through the seating member 50 `as Shown in FIG. 3. However, in the pump assembly`250, an engine cylinder 256 is threaded onto the upper end of the middle plug 124, and the pump unit does not utilize a jacket as in the pump assembly 34. The engine piston assembly 150 is of a size to reciprocate in the engine cylinder 256 upon the imposition of high pressure power iiuid in the lower end of the engine cylinder. Also, in this embodiment, the passageway 172 is in communication with the lower end of the engine cylinder 256 to direct power fluid from the annular chamber 118 below the packer 166 in substantially the same manner as previously described.

A bypass extension member 258 is threadedly secured to the upper end of the engine cylinder 256 to form the upper head for the engine cylinder and to control the iiow of fluid around the pump assembly 256, as will be described. The extension assembly 256 comprises an elongated body member 266 having a bore 262 extending through the major portion of the length thereof and communicating with downwardly and outwardly extending ports 264 at the lower end of the body 260 immediately above the upper end of the engine cylinder 256. A bypass valve seating member 266 is slidingly sealed in the bore 262 by suitable packing 26S and is constantly urged in an upward direction by a spring 276 reacting against the lower end of the bore 262. The upper end of the seat member 266 is connected to arms or fingers V272 which extend upwardly along the walls of the bore 262 and then inwardly toward a projection 274 of a head member 276 threadedly secured in the upper end of the bore 262. The upper ends of the arms 272 are connected to the projection 274 by a shear pin 278, such that the seating member 266 may be released from the projection 274, as will be described. It may also be noted in this connection that the lower end of the seating member 266 is positioned slightly above an upwardly facing shoulder' 250 in the bore 262 when the arms 272 are connected to the projection 274 by the shear pin 278. Y

Ports 282 extend through the head member 276 to provide a continuation o-f the bypass passageway through the extension member 258, and a suitable fishing neck 284 is preferably formed on the upper end of the head member 276 for retrieving the entire pump assembly 250 in the event of a malfunction of parts.

A ball type valve 286 is provided with a bore 283 therethrough for slidingly receiving a cylindrical portion 29() on the lower end of the projection 274. The ball 2S6'is of a size to mate with the seating member 266 and normally prevent a downward ow of iiuid through the boreY 262, but may be moved upwardly on the cylindrical pro jection portion 296 to open the bore 262 for an upward flow of fluid therethrough. The upward movement ofk the ball 236 is limited by a shoulder 292 at the upper end of the cylindrical projection portion 290i A suitable packer 294 is secured' around the peripheryk of the extension member 258 and is held in the desired position by suitable rings 296 mounted between a shoulder 298 on the outer periphery of the `body* member 261i and the head portion 276. The packer 294 is of a size to provide a sliding seal of the extension member 258 in the production tubing V26 for moving the pump assembly 250 upwardly and downwardly inthe production tubing, as will be described; Y Y

Operation of embodiment shown in FIGS. 7-9

Theoperation of the modified pump assembly 25) is best illustrated in FIGS. 8 and 9. The pump assembly 250 is installed in theY pump cavity housing 32 in sub-Y stantially the same manner as in the pump assembly 34- previously described, in that the cap 38 (FIG. l) is removed frorn the upper end'of the production tubing 26 and the pump assembly 250 is inserted in the productionV tubing to a point below theconnection of the controlV valve e@ to the production tubing. Upon replacing of the cap 36, the control valve 4ii`is`positioned such that luid at an elevated pressure is directed from the supply conduit 44 into the upper end of the ,production tubing 26, and the upper end of the power tubing 28 is connected to the exhaust conduit 46. 'I'he higher pressure uid imposed in the upper end of the production tubing 26 will act downwardly on the bypass valve 286 and hold this valve closed in the position shown in FIG. 9. Therefore, the higher pressure fluid acts across the entire cross sectional area of thepump assembly 250 to pump the assembly downwardly through the production tubing into the pump cavity housing 32. Fluid below the downwardly moving pumpV assembly 250 is forced upwardly through the power tubing 28 into the exhaust conduit 46.

As the pump assembly 256 enters the pump cavity housing 32, theY lower packing 88 enters the seating shoe 52 and the extension 110 at the lower end of the pump unit is telescoped into the upper end of the seating member` 51) in the manner shown in FIG. 8 to open the recovery valve 96. Therefore, the passageV 92 is open and fluid having a pressure equal to the static pressure ofV uid at the lower end of the power tubing 28 is admitted to the seating member 56 and seating shoe 52 to hold the tubing `standing valve assembly 60 closed in the same manner as in the embodiment previously described.

The control valve 40 is then shifted to reverse the flow in the power and production tubings to impose high pressureppower uid at pump operating pressure in the chamber 11Saround the pump assembly between the packer 160 andthe lower packing 88 to hold the seating member 50 down; raise the pump unit 250, and telescope the pumprunit extension 110 upwardly in the seating memberrSt); During this upward movement of the pump u nit extension 110, the fluid acting on the recovery valve 96' will close this valve against the action of the spring 100 in the same manner as previously described to provide a pumping action in the seating member 50 and reduce the pressure of fluid in the seating member 50 and seating shoe 52 to Well fluid pressure. It should again be noted here that the spring 72 in the tubing standing valve assembly 60 is of a strength to resist any leakage of high pressure iluid, which may occur around the packing 88 and 112, such that the valve 64 will open and the pressure in `the seating member 50 and seating shoe 52 will be reduced to well fluid pressure during the upward movement of the pump unit extension 110, prior to the operation of the pump unit. n

When the pump unit 250 has been moved upwardly to operating position as illustrated in FIG. 9, high pressure power uid' from the chamber 118 ilows through Ythe passageway 172 in the middle plug 124 into the lower end of the engine cylinder 256 to operate the engine piston assembly 15@ ina normal manner. During reciprocation of the'gpump piston 13:8,` well liuid is drawn upwardly through'the tubing standing valve assembly 60, the pump standing valve 132 and through the pump piston for dischargeupwardly through the passageway 158 into the annular chamber 299 between the engine cylinder 256 and the inner periphery ofthe production tubing 26. This upwardly moving uid flows inwardly through the Yports 264 in the extension 'assembly 25S to act upwardly on the bypass valve 286 and open this bypass valve,rsuch that the'fluid may Vflow on upwardly through-the bore 262 and ports` 282 into the production tubing 26 abo'v'e the pump assembly 250. Therefore, the bypass Valvey 286 provides no appreciable resistance to the flow of uid being pumpedV by the pump' assembly 250, and this uid may be easily forced von upwardly through the production tubing 26 to the surface of the well. i

When it is desired to remove thepump assembly 250- for a repairj orthe like, the control valver40 is again tubing 26-and connect the power tubing=28 to exhaust pressure. This highrpressure iluidin the production tubing 26 again-closes thefbypass valve'286lagainst its seat 266 and imposes high'pressure fluid across theentire 1 7 cross sectional area of the pump unit 250. This downwardly yacting hydraulic force on the pump assembly 250 telescopes the pump unit extension 110 back into the seating member 50 against the trip rod 98 to open the recovery valve 96 in the manner shown in FIG. 8. The pressure of the iluid in the production tubing 26 is then increased suiliciently to force both the bypass valve 286 and the seating member 266 downwardly against the action of the spring 270 and the shear pin 278 (see FIG. 7) until the shear pin 278 is broken.

The control valve 40 is then again reversed to reverse the ilow of fluid in the power and production tubings, such that high pressure fluid is again imposed in the annular chamber 118 surrounding the lower end portion of the pump assembly. Since the recovery valve 96 is then open, high pressure fluid ows through the passage 92 into the seating member 50. However, when the ow of uid in the power and production tubings is reversed, the spring 270 moves the seating member 266 and bypass valve 286 upwardly to the position shown in FIG. 8, where the bypass valve 286 engages the shoulders 292, and the bypass valve is held closed. At this time the bore 262 through the extension member 258 will be closed and no uid can then ow upwardly 4through the pump unit and extension member 258. Therefore, relatively high pressure uid is retained in the seating member 50, as well as in the annular chamber 118, to provide upwardly acting high pressure fluid across the entire pump assembly 250` and force the pump assembly upwardly through the production tubing 26. When the pump assembly 250 is removed from the upper end of the production tubing 26, the shear pin 278 is replaced before the pump assembly is re-run in the well.

In summarizing the operation of the pump assembly 250, it will be observed that the pump assembly is easily pumped downwardly through the production tubing into a seated position in the pump cavity housing 32 by the imposition of fluid at a slightly elevated pressure in the upper end of the production tubing. When the pump assembly 250 is seated in the pump cavity 32, the ow through the power and production tubings is reversed to extend the pump assembly upwardly with respect to its seating member 50, which provides a downwardly acting 'hydraulic bias across the packing 88 and retains the pump assembly in a stable pumping position. When it 'is desired to remove the pump assembly 250, flow 4through the power and production tubings is again reversed to move the pump unit downwardly in the seating member 50, and the pressure in the production tubing is increased to such an extent as to break the shear pin 278 in the bypass assembly 258. Flow through the power and production tubings is again reversed to impose an upwardly acting hydraulic force on the pump yassembly and close the bypass valve 286 in the etxension 258 against the upward ow of uid; whereupon the pump assembly 250 is pumped upwardly through the production tubing 26 to the surface of the well.

Embodment shown in FIGS. 10 and 11 A modified bypass extension assembly 300 of the type shown in FIGS. lO` and 11 may be used with a pump assembly 250 of the type shown in FIGS. 7-9 instead of the bypass extension assembly 258 previously described. The assembly 300 comprises an elongated body 302 threadedly secured in the upper end of the engine cylinder 256 to form lthe upper head of the engine cylinder, and has a bore 304 extending from the upper end of the body into the lower end portion of the body. A plurality of ports 306 provide lcommunication between the lower end 308 of the bore 304 and the annulus 299 provided between the pump assembly 250 and the production tubing 26. Also, a head member 310 is threadedly secured in the upper end of t-he bore 304 and has vertical ports 312 therethrough communicating with the bore 304 for the flow of uids from the pump assembly 250 upwardly through the production tubing 26, as will be described.

v18 Also, a shing neck 314 may be formed on the upper end of the head member 310, if desired.

A valve sleeve 316 is sliding/ly disposed in the bore 304 and has a reduced diameter extension 318 on the lower end thereof extending into a smaller bore 320 formed in the body member 302 at the lower end of the bore 304. Vertically spaced, circumferential grooves 322 and 324 are formed in the outer periphery of the valve sleeve extension 318 to alternately receive a ball type detent 326. The detent 326 is urged inwardly toward the small bore 320 by a spring 328 anchored against a plug 330 suitably secured in a mating bore or aperture in the side of the body member 302. It is believed apparent that the detent 326 functions to hold the valve sleeve 316 in a xed position in the bore 304 when the detent is received in one of the grooves 322 or 324, and that the valve sleeve 316 may bet moved vertically to alternately poosition the detent 326 in the grooves 322 and 324.

An upwardly facing annular valve seat l332 is formed on the upper end of the valve sleeve 316 to receive a valve member 334 which cooperates with the valve sleeve 316 in preventing the downward ow of lluids through the bore 304 when the valve member is seated on the valve seat 332. The guide rod 336 of the valve member 334 extends downwardly through the reduced diameter end portion 318 of the valve sleeve 316 for retaining the valve member 334 concentric with the valve seat 332.

A suitable packer 338 is secured around the periphery of the extension assembly 300 between the ports 306 and the ports '3112 by means of holding rings 340 being urged downwardly by the head member 310. The packer 338 is of a size to provide a sliding, sealing t thereof in the production tubing 26 in the same manner as the packer 294 in the extension assembly 258 previously described.

When the extension assembly 300 is utilized on the pump assembly 250, the valve sleeve 316 is positioned in its upper position as shown in PIG. l0, then the pump assembly 250 is inserted in the upper end of the production tubing and pumped downwardly through the production tubing in the same manner as previously described. When higher pressure fluid is imposed above the extension assembly 300 than is present below the pump assembly 250, the valve member 334 is retained in a closed position on the valve seat 332 to prevent a downward flow of Huid through the bore 304, such that the pump assembly 250 may be pumped downwardly through the production tubing. It may be noted, however, that the pressure of the uid in the production tubing above the extension assembly 300 is only slightly higher than the pressure below the pump assembly 250, such that the valve sleeve 316 will be retained in its upper position with the detent 326 in the lower groove 322 as illustrated in FIG. 10.

When the pump assembly 250 is seated in the pump cavity housing 32 in the manner previously described,

and when the pump assembly 250 is placed in operation by the direction of high pressure uid through the power tubing 28 at pump operating pressure, the uids pumped by the pump assembly 250 will `flow upwardly through the annulus 299 around the engine cylinder 256 and then inwardly through the ports 306. This pumped iluid will provide an upwardly acting pressure differential across the valve member 334 to raise the valve member 334 to a position against the head 310, such that the pumped uid may ilow around the valve 334 on upwardly through the ports 312 and into the production tubing above the extension assembly 300. V

When it is desired to remove the pump assembly 250 with the extension assembly 300 on the upper end thereof, the ow of iiuid through the production and power tubings is reversed to provide a higher pressure in the production tubing than occurs in the power tubing. Thisincrease in pressure in the production tubing above the extension assembly 300 closes the valve 334 and then telescopes the pump assembly 250 in the manner previously described. The` pressure in the production tubing is then 19 increased to' 'such an extent that the valve sleeve 316 Yand valve member 334 are forced downwardly in the'b'ore 304 against the action of the detent 326. YWhen the valve sleeve 316 is forced downwardly to the position shown in FIG. ll, the detent 326 is positioned in the upper circumferential groove 324, and the valve sleeve 316 is positioned in closed relation over the ports 306. Therefore, when the flow in the production and power tubings is again reversed to remove the pump assembly 250 in the manner previously described, no uid can flow upwardly -through the bore 304 and high pressure power fluid will be imposed across the entire cross sectional area of the pump assembly, in substantially the same manner as when using the extension assembly 258. As a result, the pump assembly 250 is easily pumped upwardly through the production tubing. It may also be noted that when the valve sleeve 316 is forced downwardly, fluid standing in the smaller bore 320 below the valve sleeve extension 318 is forced upwardly through a restricted passageway 342 which provides communication between the lower end of the `smaller bore 320 and the exterior of the body 302. Therefore, only the detent 326 will resist the downward 'movement of the valve sleeve 316.

When the pump assembly 250, having the extension assembly 300 on the upper end thereof, is removed from the well installation, the valve sleeve 316 is manually moved back upwardly to the position shown in FIG. l with the detent 326 seated in the lower circumferential groove 322, prior to re-running the pump assembly in the well.

Embodmenl shown in FIGS. 12-15 v -As previously indicated, the present Vinvention contemplates a subsurface pump installation wherein the pump unit may be pumped partially out of a wellbore and then returned downwardly to a pumping position, without the necessity of completely removing the pumpunit from the well when the pump unit is once unseated from its 'pumping position. This embodiment of the invention is illustrated in FIGS. 12 through l5 and comprises another modified bypass extension assembly 350 which may be utilized with the pump assembly 250 previously described in connection with FIGS. 7.8 and 9.

The extension assembly 350 comprises a lower body member 352 having its lower end externally threaded for connection with the upper end of the engine cylinder 256, as illustrated in FIG. l2, such that the body member 352 forms the upper head for the engine cylinder. A bore 354 extends from the upper end of the body 352 yto adjacent the lower end of the body to slidingly receive a valve sleeve 356. It may also be noted that a slightly enlarged 'counter bore 358 is formed at the lower end of the bore 354 and communicates with the outer periphery of the body 352 through a restricted passageway 360, for purposes which will be described. The valve sleeve 356 has its lower end`362 closed and has a plurality of circumferentially spaced ports 364'slightly above the closed lower end 362 which mate with ports 366 formed in the body 'member 352 when the valve sleeve 356 is in an upper position as illustrated in FIG. 12.

A tubular body portion 368 is threadedly secured around the upper end of the body 352 above the ports 366 and is reduced in diameter at 370 to support a packer 372 around the upper end thereof. The packer 372 is held Abetween a pair of rings 374, with the lower ring 374 being urged against the upwardly facing shoulder 370 of the body member 368 -by a head member 376 threadedly secured inthe upper end of the'body 368. The packer 372 is of a size to provide a sliding, sealing iit thereof in the production tubing 26 of a well installation and prevent a bypassing `of fluid around the extension assembly 350, in the same manner as described in connection with the previous extension assembly embodiments.

Ports 378 are 4formed vertically through the head portion 376 vin communication with the interior of the tubular v2i) bodyportin 368 and in communication with the bore 354 of the lower Vbody member 352.

A ball type valve 380 is slidingly 'secured Von a cylindrical projection 382-extending downwardly from the central portion of 'the head member 378, and is limited in its upward movements by a downwardly facing shoulder 384 formed at the upper end of the cylindrical projection 382. The valve member 380 is of a size to mate with an annular valve seat 386 formed on the upper end of the valve sleeve 356 and prohibit downward llow of uid through the extension assembly 350 when a downwardly acting pressure differential is imposed across the valve 380.

A ratchet type control member, generally designated by reference character 388, is positioned in the tubular body member 368 between the upper end 390 of the lower body member 352 and a downwardly facing shoulder 392 formed on the inner peripheryof the tubular body member 368, to cooperate with radially extending and opposed lugs or cams 394 secured in the upper end portion of the valve sleeve 356. In a commercial embodiment of this invention, the ratchet member 388 is formed by an upper segment 396 and a lower segment 398 held in fixed positions with respect to one another by a sleeve 400, to provide a continuous slot 402 around the circumference of the ratchet member which receives the cams 394 of the valve sleeve 356. The ratchet member 383 is most clearly shown in FIG. 15 where the ratchet member is illustrated as being laid out flat to illustrate the configuration of the slot 402 and to more clearly illustrate the operation of the ratchet member.

As illustrated in FIG. 15, the slot 402 is somewhat sawtoothed in configuration, and, starting with the left `hand end of FIG. l5, includes a downwardly slanted leg portion 404 having a rounded lower end 406 which forms a seat for one ofthe cam members 394 in one position of the valve sleeve 356, as will be described. An upwardly `slanted leg portion 4018 extends from adjacent the lower end 406 of the'downwardly slanted leg portion 404 in such a manner as to guide a cam 394 upwardly through the leg portion 408 in theevent the cam is urged upwardly from the lower end or socket 406 of the leg portion 404. A vertically extending leg portion 410 extends upwardly from the extreme upper end of the upwardly slanted leg portion 408 to further guide one 'of the cam members 394 in the event the cam member is urged upwardly when in the leg portion 408. Another downwardly slanted leg portion 412 extends from adjacent the upper end ofthe leg portion 488 4to receive and guide a cam member 394 being moved downwardly through the vertical leg portion 410. It will be noted in Vthis regard that the lower edge 414 of the leg portion 412 extends beyond the center line of the vertical leg portion `410, such that a cam being moved downwardly through the leg portion 410 will enter the leg portion 412, Vrather than the adjacent leg portion 408. Another upwardly slanted leg portion 416 extends from adjacent the lower end 418 of the downwardly slanted leg portion 412. The next downwardly slanted leg portion 404 intersects the leg portion 416 slightly below the upper end 420 thereof. The construction of the remainder of the slot 402, including the second-mentioned leg portion 404, is symmetrical to complete the construction of the slot around the entire circumference of the ratchet member 388. It will be understood that the opposite portions of the slot 402 are symmetrical, since two of the cams 394 are provided on the valve sleeve 356 and these cams are positioned in opposed relation.

As previously indicated, the sections or segments 396 and 398 of the ratchet 388 are indexed and held in the desired 'spaced relation by a sleeve 400, such that the opposed cams 394 will extend into identical portions of the Yslot 402` and the cams 394 will have a sliding tit in the slot 402. It may also be noted that the length of the ratchet member 388 is preferably such that the ratchet member may rotate in the tubular housing 368 between -assaoos 21 ythe shoulders 390 and 392 during operation of the assembly, as described below; v

When utilizing the extension assembly 350 on the upper end of a pump assembly 250 in the production tubing 26, the valve sleeve 356 and valve ball 380 are responsive to pressure differentials placed across the extension assembly for operation of the cams 394 in the ratchet 388. Whenever a high pressure is imposed above the extension assembly 350, as when the pump assembly 250 is being pumped downwardly through the production tubing to a pumping position, the pressure of the iluid acting on the ball valve 380 and the upper end of the valve sleeve 356 will urge the valve sleeve 356 downwardly until the cams 394 are positioned in opposed sockets '406 or 418 at the lower end of opposite leg portions 404 or I412 in the ratchet member. It may also be noted here that the lower end of the bore 354 is in constant communication with the uid pressure below the packer 372 by means of the restricted passageway 360, to facilitate the downward movement of the valve sleeve 356 when a downward pressu-re diiferential is imposed across the extension assembly. This lower most position of the valve sleeve 356 and valve ball 380 is illustrated in FIG. 13. And, in this position of the assembly 350, -it will be observed that the valve sleeve 356 is in closing relation over the ports 366 to assure that no fluid can ow through the extension assembly 350 in either direction.

When an upward pressure differential is imposed across the packer 372, as when the pump assembly 250 is being raised to pumping position, a higher pressure uid is provided communication through the restricted passageway 360 against the lower end 362 of the valve sleeve 356, such that the valve sleeve 356 will be urged upwardly in the bore 354. Assuming that each cam 394 was in a socket portion 406 as illustrated at the leiit hand end of FIG. when the valve sleeve 356 was in a position shown in FIG. 13, and assuming that an upwardly acting pressure differential is imposed across the packer I372, each cam 394 will be moved upwardly through the adjacent slanting leg portion 408 and then :on upwardly through the `adjacent vertical leg portion 410. As a result, the valve sleeve 356 is moved upwardly to the position illustrated in FIG. l2 where the ports 364 in the v-alve sleeve 356 are in communication with the ports 366. This is considered the pumping position of the extension assembly, since fluid being pumped by the pump assembly 250 Ymay iiow upwardly through the ports 366, ports 36'4, valve sleeve 356 to raise the ball valve 380, land then these pumped fluids may flow on upwardly through the ports 378 into the production tubing above the packer 372.

The next time a downwardly acting pressure differential is imposed across the packer 372, the valve sleeve 356 will be moved downwardly with the cams 394 being moved through the downwardly slanting leg portions 412 extending from the lower ends of the vertical leg portions 410. The valve sleeve 356 will therefore assume the position shown in FIG. 13 and previously described.

When an upwardly acting pressure differential is again imposed on the packer 372, the cams 394 will be moved upwardly through the adjacent leg portions 416 into the socket portions 420; whereupon further upward movement of the valve sleeve 356 will be prevented. This position of the valve sleeve 356 is illustrated in FIG. 14 where it will be observed that the Valve sleeve still is in closing relation over the ports 366 to prevent ow of fluid in either direction through the extension assembly 350.

To review the operation of the extension assembly 350, it will be apparent that the valve sleeve 356 is moved upwardly and downwardly in response to pressure differential across the packer 372. When the eX- tension assembly 350 is rst run in a well for movement I of the pump assembly 250 downwardly to a seating posishown in FIG. Y13 for closing iiow of fluid .through the extension assembly and facilitating thedownward pumping action of the pump assembly 250. When the pump assembly 250 is seated and the ow of iiuid through the power and production tubings is reversed, the cams 394 will be moved upwardly to the upper ends of the vertical leg portions 410. The valve sleeve 356 will then be in a pumping position as illustrated in FIG. l2 for a normal pumping operation of the pump assembly 250. When the flow in the power and production tubings is again reversed prior to pumping the pump assembly 250 out of the production tubing, the valve sleeve 356 will be moved upwardly to the position illustrated in FIG. 14 where iiow of uid through the extension 350 in either direction is prevented. Therefore, the pump assembly 250 may be pumped upwardly through the production tubing in the same manner as previously described in connection with the embodiment shown in FIGS. l0 and 1'1 when upward flow of iiuid through the pump assembly is prevented.

In the event it is desired to return the pump assembly 250 to a pumping position, flow of liuid through the power and production tubings is simply again reversed. When this occurs, the valve sleeve 356 will be moved back downwardly to the position illustrated in FIG. 13 until the pump assembly 250 is seated in the pump cavity housing. Then, when ow of fluid through the power and production tubings is again reversed to provide a pumping operation, the Valve sleeve 356 is moved back upwardly to the position shown in FIG. l2vwhere the uid being pumped by the pump assembly 250 may flow upwardly through the extension assembly 350 and then on upwardly to the top of the well. Since the slot 402 is continuous, the extension assembly 350 may be raised and lowered to any desired extent in the production tubing, such as when running soluble plugs inthe production tubing for removing paraffin. Each time the extension assembly 350 is raised, it may again be lowered to a pumping position without the necessity of completely removing the pump assembly from the well.

From the foregoing it will be apparent that the present invention may utilize a free pump tubing and pump cavity installation and yet provide -a `downward ow of high pressure power uid through the smaller tubing for operating a subsurface hydraulic pump and an upward iiow of production fluid through the larger stringof tubing. The subsurface hydraulic pump may be partially removed from the well and then reseated in the. pump cavity at the lower end of the well. It will alsoy be apparent that the present invention provides a sub-surface hydraulic pump installation wherein all of the downwardly acting hydraulic bias on the pump assembly is removed when the pump assembly is being unseated from its pumping position, such that a minimum force is required for unseating the pump assembly 4and moving the pump assembly upwardly through the well. It will be further apparent that in the present subsurface hydraulic pump installation the pump assembly may be pumped out of -a well with a minimum hydraulic pressure, yet the pump assembly will be stable during a normal pumping operation.

Changes may be made in the combination and arrangement of parts or elements as heretofore set forth in the specification and shown in the drawings, it being understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention as defined in the following claims.

I claim:

-1. In a uid operated pump system for a well, the combination of: a production tubing extending downwardly into the well, a power tubing extending downwardly into the well and connected at its lower end to the lower end portion of the production tubing, a supply of high pressure liuid connected to the production and power tubings for alternatelyY subjecting said tubings to high pre'ssure' Huid, an annular seat lin the lower end of theproduction tubing belowthe connection of the power tubing to the production tubing, a seating shoe engaging said annular seat, an upwardly opening standing valve assembly carried by the seating shoe for admitting well vuidtinto the seating shoe and restricting downward iiow f fluid through the seating shoe, an elongated pump assembly in the production tubing seated in said seating shoe and having a well fluid inlet in its lower end communicating with said seating shoe for retaining well l'iuid pressure in said shoe during operation of the assembly and providing a downwardly acting hydraulic bias on the pump assembly, said pump assembly having an exhaust port above said inlet, a packer carried by the pump assembly between said `well fluid inlet and exhaust port to form an annular chamber between said packer and said annular seat, said power tubing being in communication with said chamber, and means for directing iiuid from said chamber into said seating shoe against the standing valve assembly and overcoming said downwardly acting hydraulic: bias `for unseating the pump assembly.

2. A system as defined in claim l wherein said pump `assembly comprises a fluid operated pump unit, and a tubular seating member sliding secured aroundthe lower vend of the pump unit and adapted to seat in said seating shoe, said pump unit being movable downward in said seating member in response to high pressure fluid in the production tubing and being movable upwardly in said seating member in response to high pressure fluid in the power tubing-and said means for directing iiuid from vsaid chamber into said seating shoe comprises means providing a fiuid passage between said chamber and said seating shoe, and recovery valve means in said' passage responsive to upward and downward movements of the -pump unit.

3. A system as defined in claim 2 wherein said passage is located in said seatingmernben'and said valve means comprises a downwardly facing valve seat, and a valve member cooperating with said valve seat and extending into the path of movement of the pump unit for opening 'the valve means upon downward movement of the `pump unit.

4. A system as defined in claim 3 wherein said valve means includes a spring biasing the valve member downwardly to 'open the valve means, said spring providing a :force less than the force imposed on the valve member by high pressure fluid flowing from said chamber through said passage.

5. A system as defined in claim l wherein said pump assembly comprises a fluid operated pump unit having a 'power uid inlet therein in communication with said `chamber, a tubular extension on the lower end of the pump unit around said well fluid inlet and having an outwardly extending stop ange on the lower end thereof, a tubular seating member telescoped over said tubular extension and extending inwardly above said vstop tiange, `iirst packing means positioned in the upper end of said Vseating member providing a sliding seal of the seating 'member around the pump unit tubular extension, second packing means carried on the lower end of said seating member sealingly engaging said seating shoe,

said pump unit being responsive to high pressure fluid in the production tubing for downward movement in said Aseating member, said packer having an outer diameter larger than the outer diameter of said second packing 'means to provide a net upwardly directed hydraulic force across the pump unit when high pressure fluid is .directed into the power tubing, and said means for directing "uid '-from said chamber into said seating shoe comprises a passage through said seating member providing com- "munication between said chamber and said seatingrshoe, and a valve in said passage extending into Vthe path of movement of lsaid tubular extension `for opening said -pas-sage Vupon downward movement of said pump unit. 6.V A 4'system as defined in claim 5 characterized further 24 toincludel a spring .in said passage urging said valve .to an open position with a force less than the force on the valve of high pressure uid flowing from said chamber through said passage.

7. 'A system as dened in claim 5 characterized further to include a spring in said seating shoe urging said standing valve assembly open with sufficientforce to retain the standing valve asembly open against leakage of iluid around said first and second packing means and from the pump unit.

8. A system as defined in claim l wherein said pump yassembly includes an engine cylinder, a pump cylinder having said -well fluid in l'et in the lower end thereof, a middle ,plug interconnecting the engine and pump cylinders initandem relation with the engine cylinder positioned'above the pump cylinder, said packer being'carried around said middle plug, saidk middle plug having a verticalA bore therethrough, an engine piston assembly in the engine cylinder, a pump piston in the pump cylinder, a connecting rod extending loosely through said vertical borerand connected at its opposite ends to the engine piston assembly and pump piston, said exhaust port being formed in said middle plug in communication with the upper 'end of the pump cylinder, said middle plug also having a passageway therethrough Vproviding'communi- `cation between the engine cylinder and sai-dannular chamber and having a by-pass port extending between saidipassageway and the upper portion of said vertical bore, and a packing device slidingly sealed around said connecting rod and inthe upper portion of said vertical bore and having its vopposite ends exposed to the pressure of uid in the "engine and pump cylinders,v said packing device being movablevertically around the connecting rodY in Vresponse to Vpressure differentials across .the opposite ends thereof for opening and closing'said by-pass Aswab cup secured around the mandrel and 'facing upwardly for sealingly engaging the inner periphery vof the production tubing and providing the retrieving device responsive to downwardly acting pressure in Vthe production tubing, and a second swab cup secured around the mandrel and facing downwardly for sealingly engaging the inner periphery of the production tubing and moving the retrieving device upwardly in the production tubing in response to high pressure uid below the downwardly facing swab cup.

l0. A system as defined in claim 1 wherein said pump assembly has means therein providing a passage between said well iiuid inlet and said exhaust port, valve means in said passage operable in a direction to allow liow of fluid from said well iiuid inlet to said exhaust port and preventing ow of fluid from said exhaust port to said well iiuid inlet, an extension on the upper end of the pump assembly having a packing assembly thereon sealingly engaging the inner periphery of the production tubing above said exhaust port, a by-pass through said extension providing communication between said exhaust port and the production tubing above said packing assembly, and by-pass valve means in said extension responsive to high pressure fluid in the production tubing above said extension for closure against fluid ow through said by-pass in either direction, whereby the pump assembly may be pumped up the production tubing upon iirst imposing high pressure uid in the production tubing to close said kby-pass valve means and then imposing high pressure fluid in thepower tubing.

1-1. A system as deiined in claimvlO wherein 'said bypass valve means comprises a sleeve movable in said bypass between a first position where uid may ow therethrough and a second position where fiuid cannot flow therethrough, a ball valve mating with the end of the sleeve remote from said exhaust port to normally prevent ow of fluid through the by-pass from above the extension, and means yieldably holding the sleeve in said first position and being responsive to high pressure fiuid in the production tubing for releasing said sleeve for movement to said second position.

12. A system as defined in claim 11 wherein said means yieldably holding the sleeve in said first position comprises a shear pin connected to the sleeve and said extension.

13. A system as defined in claim wherein said bypass valve means comprises an annular seating member slidingly fitting in said by-pass, a shear pin connecting said seating member to said extension, a spring urging said seating member upwardly against said shear pin, a projection in said -by-pass above said seating member having a downwardly facing shoulder thereon, and a ball valve slidingly supported on said projection below said downwardly facing shoulder, said ball valve being of a size to mate with said seating member for normally preventing downward flow of fluid through said seating member.

14. A system as defined in claim 11 wherein said means yieldably holding the sleeve in said first position comprises a spring-loaded detent carried by said extension, 'and a groove in said sleeve for receiving the detent.

15. A system as defined in claim 10 wherein said bypass includes a bore extending vertically through a portion of said extension and a port through the extension communicating with an intermediate portion of said bore and said exhaust port, and said by-pass valve means comprises a valve sleeve slidably disposed in said bore and having a port in the medial portion thereof, a valve mating with the upper end of the valve sleeve to prevent downward flow of fluid through the valve sleeve, and a spring-loaded detent carried by the extension and being urged into said bore, said valve sleeve having a pair of vertically spaced circumferential grooves therein a1'- ranged to receive said detent for alternately positioning the valve sleeve with said ports in the valve sleeve and extension in communication and, alternately, out of communication.

16. A system as defined in claim 10 wherein said bypass includes a bore extending vertically through a portion of said extension and a plurality of ircumierentially spaced ports communicating with a medial portion of said bore and said exhaust port, and said by-pass valve means comprises a valve sleeve slidably positioned in said bore and being responsive to pressure differentials across the opposite ends thereof for movement vertically in said bore, said valve sleeve having a plurality of ports in a medial portion thereof arranged to mate with said ports in the extension in one position of the valve sleeve, land control means carried by said extension for successively guiding said sleeve between said one position and at least one lower, second, position in response to successive reversals of pressure across the valve sleeve, whereby the valve sleeve may be moved to any of its operating positions bycontrolling the ow of high pressure fluid through said power and production tubings.

17. A system as defined in claim 16 wherein said extension has a passage therethrough providing constant iiuid communication between said exhaust port and the lower end of said bore below said valve sleeve, and

wherein the lower end of said valve sleeve is closed.

18. A system Ias defined in claim 17 wherein said bypass valve means also includes a ball valve of a size to mate with the upper end of the valve sleeve, and a guide carried by said extension limiting the upward movement of the ball valve, said ball valve having a diameter less than the diameter of said bore.

19. A system as dened in claim 16 wherein said control means comprises a cam follower secured to the valve sleeve and extending radially outward therefrom, and tubular ratchet means telescoped over the valve sleeve and having a continuous slot therein slidingly receiving said cam follower, said ratchet means being secured in a fixed vertical position in said extension.

20. A system as defined in claim 18 wherein said ratchet means comprises a pair of vertically spaced tubular segments having their mating edges shaped to form said slot around the circumference of the ratchet means.

References Cited in the file of this patent UNITED STATES PATENTS 2,338,903 Coberly Ian. 11, 1944 2,653,545 Dempsey et al Sept. 29, 1953 2,851,854 Coberly Sept. 16, 1958 2,869,470 Coberly Jan. 20, 1959 2,910,945 Coberly Nov. 3, 1959 2,911,000 ensuit Dee. 15. 19,59

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 2988,oo5 June 13 1961y Charles L English It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 51 line 4, for "presure" read -w pressure line l8 for "presures" read pressures --g column 9 line IOq for "understano" read understood --g line 59 for "pasasgeway" read passageway column 10 line 18, for l "illusrated" read illustrated column l2 line ll, for "connnect" read connect --,7 column l7 line 53v for "etxension" read extension column 18 line l?? for "het," read be --g same line 17,I for "poosition" read position column 23,1 line 24I for "sliding" read slidingly column 24v line 8 for "asembly" read assembly column 26l line 46V for "2U85l9854" read Signed and sealed this 12th day of December 196i.

(SEAL) Attest:

DAVID L. LADD A v .v ERNEST W SWIDER Commissioner oi Patents y Attesting Officer 

